<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <script>
        var a = 10 
        console.log(a); // 10
        a += 10
        console.log(a); // 10 + 10    20 
        a -= 10 
        console.log(a); // 20 - 10    10
        a *=10
        console.log(a); // 10 * 10    100
        a /= 10
        console.log(a); // 100 / 10   10
        
    </script>
</body>
</html>